The Associated Press
FILE - In this Tuesday, March 7, 2006 file photo, life-sized Tyrannosaurus rex models are unloaded for a dinosaur exhibition in Potsdam, Germany. A study released on Thursday, April 15, 2021 calculates that 2.5 billion Tyrannosaurus rex prowled North America over a couple million years or so, with maybe 20,000 at any given time. (AP Photo/Sven Kaestner)
One Tyrannosaurus rex seems scary enough. Now picture 2.5 billion of them. That’s how many of the fierce dinosaur king probably roamed Earth over the course of a couple million years, a new study finds.
Using calculations based on body size, sexual maturity and the creatures’ energy needs, a team at the University of California, Berkeley figured out just how many T. rex lived over 127,000 generations, according to a study in Thursday’s journal Science. It’s a first-of-its-kind number, but just an estimate with a margin of error that is the size of a T. rex.